PACIFIC COAST OLIGOCH.f^TA. 171 



was undeveloped. One of the setae is a trifle more curved than the other. The 

 point of each penial seta shows a slight and indistinct ornamentation (fig. 144). 

 Since my first description of B. Troyeri I have found some more mature specimens at 

 the old locality in San Francisco. One of these specimens possessed two penial seta? 

 in each sac, both slightly .sigmoid, with trace of ornamentation at the free apex. In 

 the variety laguiuc the ornamentation is more distinct. 



Common seUe resemble the type, but setae a and b next posterior to clitellum 

 reach their proper and final distance from each other only in the fifth somite posterior 

 to clitellum, while in I). 7'roijeri type they reach the final di-stauce in the third somite 

 posterior to clitellum. 



• INTERNAL CHARACTERS. 



Spermathecse are much larger in the variety lagmue, or about twice the size of 

 those in B. Troyeri, with the main body distinctly contracted at the center, and with 

 the apical part much enlarged. The diverticula are distinctly tri-digitate and reach 

 up to the narrow contraction of the main sac. 



Prostates or spermiducal glands are much more slender and longer than in 

 D. Troyeri type, and generally but not always confined to one somite. 



Ovisacs are two, projecting from the septum xiii/xiv into xiv, occupying the 

 largest part of the coelomic cavity in the latter somite. The structure of the ovisac 

 is characterized by numerous trabecula forming an extensive system of round pockets 

 of various sizes. Where there are no pockets there are solid zones of round or slightly 

 oval nuclei (fig. 147) imbedded in a dense mass of tissue without distinct cell-walls. 



PHCENICODRILUS Eisen. 



The finding of a new species of this genus enables me to more properly define 

 it. The genus was originally based on the absence of a prostate at the male-pore, 

 there being, however, a short muscular atrium, in which opened the sperraduct. The 

 type was Phmicodvilas taste, a species from the Cape Region of Baja California. 

 The new species described below under the name of Fhoinicodriliis tepicensis possesses 

 a much more developed atrium, in shape and .structure resembling a spermatheca. 

 There is a total absence of glandular cells, such as are found in prostates, the whole 

 atrium being muscular. There is besides another difference between Phffinicodrilus 

 and Ocuerodrilus, though of much smaller importance. In Fhoenicodrilus we find a 

 large number of muscular fascicles divided in three paired groups in somite xvii, radiat- 

 ing from the male pore. In Ocnerodrilus these arciform muscles are few in number. 

 In Fhoenicodrilus these muscles are so thick and numerous that the atrium itself can 

 only be seen in sections, not by suface view of the inner side of the body-wall. 



Through the possession of a muscular atrium this genus comes rather close to 

 Nannodrilus Beddard. This genus, of which so far only one species is known from 

 Africa, possesses a muscular bursa copulatrix, in which opens separately the anterior 

 prostate and the anterior spermduct. The great similarity between the\atrium in 

 Fhoenicodrilus and the bursa copulatrix of Nannodrilus is very striking, especially as 



Memoirs, Vol. II, 5. January 28, 1896. 



